JPH1069077A - Positive type resist composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a positive type resist material excellent in a uniformity, having a high sensitivity and a high resolution and excellent also in a heat resistance and a property of a film endurance by using novolak resin having properties of both an alkali-soluble resin and a sensitizer and a dissolution accelerator having phenolic hydroxyl groups as an essential components. SOLUTION: This positive type resist compsn. contains a resin having repeating units represented by formed I and a wt. average mol.wt. of 1,000-10,000, a dissolution accelerator having phenolic hydroxyl groups represented by formula II and a solvent dissolving them. The amt. of the dissolution accelerator is 0.5-10 pts.wt. per 100 pts.wt. of the resin. In the formula I, 2-27% of R's are a residue of 1,2-naphthoquinonediazido-4-sulfonic ester and/or a residue of 1,2-naphthoquinonediazido-5-sulfonic ester, the remainders are H, (K) is an integer of 0-3 and (s) is a number satisfying the wt. average mol.wt. In the formula II, each of (m) and (p) is an integer of 0-3, (n) is 1 or 2, (q) is an integer of 1-3 and (r) is 1 or 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novolak type positive resist composition which provides a resist film having high resolution, excellent heat resistance and excellent residual film properties.

[0002]

2. Description of the Related Art
Novolak-based resist compositions have been prepared using two components, a novolak resin and a photosensitive agent, as main components. However, in order to obtain a resist composition having higher resolution, excellent heat resistance, excellent residual film properties, and suitable for the wavelength of the light source of various exposure machines, various efforts have been made from both the novolak resin and the photosensitive agent. To give an example from the viewpoint of novolak resin,
When the average molecular weight of the novolak resin to be synthesized is reduced, the resolution as a resist is improved, but the heat resistance and the residual film property are deteriorated (BREAK THROUGH, 1).
February 992, p. 18). For this reason, a method of removing the low molecular weight novolak resin from the synthesized novolak resin by a treatment such as a reprecipitation method has been proposed. Also,
For example, in terms of the photosensitizer, when the light source of the exposure machine changes from g-line to i-line, it is difficult for the benzophenone-based photosensitizer conventionally used to transmit light in the resist film. Proposals have been made to use a non-benzophenone-based photosensitizer that absorbs less at the i-line (Nikkei Microdevices, April 1992, p. 45).

However, in order to realize a resist composition having a higher resolution by combining these methods, many additional steps are required in the manufacturing process of the resist composition, and disadvantages such as an increase in cost are caused. there were.

The present invention has been made to improve the above circumstances, and has as its object to provide a novolak-based positive resist composition which provides a resist film having high resolution, excellent heat resistance and excellent residual film properties. And

[0005]

Means for Solving the Problems and Embodiments of the Invention The present inventors have conducted intensive studies to achieve the above object, and as a result, have found that cresol having a repeating unit represented by the following general structural formula (1) or In an alkali-soluble resin such as a xylenol novolak resin, a resin having a weight-average molecular weight of 1,000 to 10,000 partially esterified with 1,2-naphthoquinonediazide-4 or 5-sulfonic acid.
A composition in which a dissolution promoter having a phenolic hydroxyl group represented by the following general formula (2) is blended in an amount of 0.5 to 10 parts by weight with respect to 0 parts by weight has excellent uniformity, high sensitivity, and high sensitivity. The inventors have found that a resist film having excellent resolution, heat resistance, and residual film properties can be provided, and the present invention has been accomplished.

[0006]

Embedded image (In the formula, R represents 2-27 mol% of 1,2-naphthoquinonediazide-4-sulfonic acid ester residue and / or 1,2-naphthoquinonediazide-5-sulfonic acid ester residue, and the remainder is hydrogen. K is an integer of 0 to 3, and s is a number satisfying the weight average molecular weight.)

[0007]

Embedded image (In the formula, m and p are each an integer of 0 to 3, n is 1 or 2, q is 1 to 3, and r is an integer of 1 or 2.)

Hereinafter, the present invention will be described in more detail.

The positive resist composition of the present invention has the following general formula (1) based on 100 parts by weight of a resin having a weight average molecular weight of 1,000 to 10,000 and having a repeating unit represented by the following general structural formula (1). It contains the dissolution promoter having a phenolic hydroxyl group represented by 2) in a proportion of 0.5 to 10 parts by weight, and further contains a solvent for dissolving them.

[0010]

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Here, in the formula (1), R is a hydrogen atom,
2-naphthoquinonediazide-4 or 5-sulfonic acid ester residue, and the ratio of the sulfonic acid ester residue is 2 to 27 mol%, more preferably 3 to 10 mol%, and k is an integer of 0 to 3. And s is a number satisfying the weight average molecular weight. When the esterification ratio is less than 2 mol%, the effect of inhibiting the dissolution of the unexposed areas in the alkali developing solution is not sufficient, and a positive pattern cannot be obtained. Is not sufficiently soluble in an aqueous alkali solution, resulting in poor resolution.

The weight-average molecular weight of this resin is 1,0.
00 to 10,000, more preferably 2,000 to 8,
If it is less than 1,000, the heat resistance is not sufficient, and if it exceeds 10,000, the resolution and sensitivity during pattern formation are poor.

In the formula (2), m and p are each an integer of 0 to 3, n is 1 or 2, q is 1 to 3, and r is an integer of 1 or 2.

Specific examples of such a dissolution promoter having a phenolic hydroxyl group include the following.

[0015]

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[0016]

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[0017]

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[0018]

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[0019]

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The amount of the dissolution promoter having a phenolic hydroxyl group to be added is 0.5 to 100 parts by weight of the resin.
It must be 10 parts by weight. If the amount is less than 0.5 part by weight, high sensitivity cannot be sufficiently attained. If the amount exceeds 10 parts by weight, deformation occurring at the bottom of the resist pattern called microgroove in the pattern shape after exposure and development. Occurs, resulting in poor pattern rectangularity.

The positive resist composition of the present invention is obtained by dissolving a resin and a dissolution accelerator in a suitable solvent so that the solid concentration is preferably 10 to 60 parts by weight.

Examples of the solvent include ethylene glycol monoalkyl ether and its acetates, propylene glycol monoalkyl ether and its acetates, diethylene glycol mono or dialkyl ethers, lactate alkyl esters, alkoxypropionate alkyl esters, and methyl isobutyl ketone. And ketones such as cyclohexanone, and acetates such as butyl acetate. These solvents can be used alone or
More than one kind can be mixed and used.

The composition of the present invention may optionally contain a surfactant such as a nonionic, fluorine-based, or silicone-based surfactant to improve coating properties.

The method of forming a resist pattern by irradiation with radiation using the positive resist composition of the present invention is not particularly limited, and it can be carried out according to a conventional method.

For example, the composition solution of the present invention is spin-coated on a substrate such as a silicon wafer and prebaked. Thereafter, ultraviolet rays are irradiated by an exposure device such as a proximity aligner or a stepper, and further, development and rinsing are performed to form a desired resist pattern. As the developer, an aqueous solution of an inorganic alkali such as sodium hydroxide or sodium carbonate, or an aqueous solution of an organic alkali such as triethanolamine, tetramethylammonium hydroxide, or choline can be used.

[0026]

The resist composition of the present invention comprises a novolak resin having the performance of both an alkali-soluble resin and a photosensitive agent, and a dissolution promoter having a phenolic hydroxyl group as main components. It can be suitably used as a positive resist material which has excellent sensitivity, high sensitivity, high resolution, and excellent heat resistance and residual film properties.

[0027]

EXAMPLES Hereinafter, the present invention will be described specifically with reference to Synthesis Examples, Examples, and Comparative Examples, but the present invention is not limited to the following Examples.

In each example, the evaluation of various properties of the resist composition was performed by the following methods. (1) weight average molecular weight Mw Toyo Soda Co. GPC column of the alkali-soluble resin (G2000H ₆ 2 present, G
Using 3000H _{6 (} 3 pieces, G4000H ₆ 1 piece), a flow rate of 1.5 ml / min, an eluting solvent of tetrahydrofuran, and a column temperature of 40 ° C. were analyzed by a GPC method using monodisperse polystyrene as a standard. (2) Resist film thickness Spin coater manufactured by Dainippon Screen (SKW-636)
-BV), the prepared resist composition was applied on a silicon wafer that had been subjected to HMDS treatment,
After soft baking on a hot plate for 0 second, the resist film thickness was measured using Nanospec M210 (trade name: optical film thickness measuring device). (3) Optimal exposure dose Eop Nikon i-line (365 nm) exposure apparatus NSR-175
Exposure was performed by changing the exposure time with 5i7A (numerical aperture of the lens: NA = 0.50), and a paddle of 23 ° C. × 150 seconds using a 2.38% aqueous solution of tetramethylammonium hydroxide (TMAH) as a developing solution. After development and rinsing with pure water, spin drying was performed. Next, 1 electron microscope (S-4100) manufactured by Hitachi, Ltd.
When a 0 μm line-and-space pattern is formed in a width of 1: 1 ratio, the exposure energy is adjusted to the optimum exposure amount E.
It was defined as op (sensitivity) and determined. (4) Resolution The separation resolution at the optimum exposure amount Eop in the above (3) is shown. (5) Heat resistance The patterned resist film on the silicon wafer was further heated on a hot plate at 130 ° C. for 5 minutes, and it was determined whether or not the 10 μm line and space pattern shape was maintained after heating. .

[Synthesis Example] In a three-necked flask equipped with a stirrer, a condenser and a thermometer, 130 g of a novolak resin having a weight-average molecular weight of 5,700 and starting with 50 mol% of p-cresol and 50 mol% of m-cresol, 1,2-naphthoquinone-2-diazide-5-sulfonyl chloride 1
4.1 g and 650 g of 1,4-dioxane were charged and dissolved. To this solution, 5.6 g of triethylamine was added dropwise at room temperature. After completion of the dropwise addition, the mixture was stirred at room temperature for 2 hours, and then the reaction solution was poured into a large amount of a 0.1N hydrochloric acid aqueous solution to recover a precipitated resin. The collected resin was dried with a vacuum drier to obtain 135 g of the desired photosensitive resin (A).

Example 1 100 g of partially 1,2-naphthoquinone-2-diazide-5-sulfonylesterified novolak resin (A) obtained in the above synthesis example, and C-34 as a dissolution accelerator Compound 3.0 represented by
g, 0.03 g of a fluorinated surfactant Fluorinert FC-430 (manufactured by Sumitomo 3M) in ethyl lactate 150
g. This solution was filtered through a 0.5 μm filter to obtain a desired positive resist composition. The obtained composition was spin-coated on a silicon wafer, and then prebaked on a hot plate at 100 ° C. for 120 seconds to form a film having a thickness of 6.0 μm. This was exposed with an i-line stepper NSR-1755i7A (manufactured by Nikon Corporation) and developed with a 2.38% aqueous solution of tetramethylammonium hydroxide. The exposure amount at this time is 620 m
At J / cm ² , it was possible to form a 1.5 μm stripe pattern.

Examples 2 to 5, Comparative Examples 1 and 2 Positive compounds obtained by blending novolak resin (A), various dissolution promoters, fluorine-based surfactants and solvents in the same manner as in Example 1 above. The mold resist composition was spin-coated on a silicon wafer in the same manner as in Example 1, and exposed and developed. Table 1 shows the results of the above examples, and Table 2 shows the results of the comparative examples.

[0032]

[Table 1]

[0033]

[Table 2]

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor: Yu Kobayashi 1-10 Hitomi, Matsuida-cho, Usui-gun, Gunma Prefecture Inside Silicone Electronics Research Laboratory, Shin-Etsu Chemical Co., Ltd. (72) Inventor Tetsuya Inukai Matsuida-cho, Usui-gun, Gunma Prefecture 1-10 Hitomi, Shin-Etsu Chemical Co., Ltd. Silicone Electronic Materials Research Laboratory (72) Inventor Hideto Kato 1-10 Hitomi, Matsuida-cho, Usui-gun, Gunma Prefecture Silicon Electronic Materials Research Laboratory, Shin-Etsu Chemical Co., Ltd.

Claims (1)

[Claims] 1. A weight average molecular weight having a repeating unit represented by the following general structural formula (1): 1,000 to 10,000.
0 of the resin having a phenolic hydroxyl group represented by the following general formula (2) per 100 parts by weight of the resin
A positive resist composition containing the solvent in an amount of 10 to 10 parts by weight, and further containing a solvent for dissolving them. Embedded image (In the formula, R represents 2-27 mol% of 1,2-naphthoquinonediazide-4-sulfonic acid ester residue and / or 1,2-naphthoquinonediazide-5-sulfonic acid ester residue, and the remainder is hydrogen. K is an integer of 0 to 3, and s is a number that satisfies the above weight average molecular weight.) (In the formula, m and p are each an integer of 0 to 3, n is 1 or 2, q is 1 to 3, and r is an integer of 1 or 2.)